This district extends along the Mokelumne River from the vicinity of Lancha Plana, Amador County, west through the Camanche-Wallace area, Calaveras County, to Clements, San Joaquin County, a distance of about 12 miles.
The creeks were first worked during the early part of the gold rush, and hydraulic mining of the terrace gravels followed. The town of Camanche was named for a town in Iowa. Later, the Chinese mined the river and reworked the old tailings. From 1904 to 1923, the river was dredged on a large scale by the American Dredging Company. Dragline dredging was done during the 1930s and bucket-line dredging from then until 1951. Much of the region was recently inundated by the Camanche reservoir. The output from dredging is estimated to be about $10 million.
The deposits consist of unconsolidated gravels in and adjacent to the Mokelumne River and floodplain deposits. Tightly packed shore gravels of Eocene age are found near Wallace. In the west portion of the dredging field, the gravels ranged from six to 50 feet deep while, in the east, they were six to 25 feet deep. Bedrock is clay and volcanic rock. Values recovered by dredging ranged from 10 to 25 cents per yard. The gold was fine grained and 850 to 900 in fineness.
American Dredging Co., 1904-23, three bucket-lines; Camanche Placers Ltd., 1935-, one bucket-line; Gold Gravei Products, 1935; Gold Hill Dredging Co., 1936-51, two bucket-lines; Lancha Plana Gold Dredging Co., 1926-40, one? bucket-line; Wallace Dredging Co., 1935-40, two bucket-lines.
Clark, W. 6., 1955, San Joaquin County, Gold Hill dredges: Cali. fornia Jour. Mines and Geology, vol. 51, no. 1, pp. 37-39.
Logan, C. A, 1927, Calaveras County, American Dredging Company: California Min. Bur. Rept. 23, p. 198.
Turner, H. W., 1894, Jackson folio, California: U. S. Geol. Survey Geol. Atlas of the U.S., folio 11,6 pp.
Tucker, W. B., 1919, Oro Water, Light, and Power Company dredges: California Min. Bur. Rept. 15, pp. 127-128.Winston, W. B., 1910, Gold dredging in California, Calaveras County: California Min. Bur. Bull. 57, pp. 205-208.